Apparatus for detecting the pressure and temperature in the intake tube of an internal combustion engine, and method for producing it

ABSTRACT

An apparatus for detecting the pressure and temperature in the intake tube of an internal combustion engine. A temperature sensor and a pressure sensor are secured to a carrier together with an evaluation circuit in a common housing with as little strain as possible. The housing includes at least two chambers separate from one another, one of which forms a pressure chamber that communicates with the intake tube via a stub and is sealed off from the environment in which the pressure sensor is secured. The other chamber serves to secure the temperature sensor therein by use of connection elements, and sealing adhesive connections that decouple mechanical strains for securing the carrier and sealing off the pressure sensor.

PRIOR ART

The invention relates first to an apparatus for detecting the pressureand temperature in the intake tube of an internal combustion engine,where a temperature sensor and a pressure sensor, the latter secured toa carrier together with an evaluation circuit with as little strain aspossible, are disposed in a common housing.

An apparatus for detecting the pressure and the temperature in theintake tube of an internal combustion engine in which a temperaturesensor and a pressure sensor are disposed in a common housing, is knownfor instance from German Patent DE 28 51 716 C1.

The combination of a pressure sensor known for instance from GermanPatent Disclosure DE 43 17 312 A1 with a temperature sensor is shown inFIG. 4.

In the pressure sensor shown in FIG. 4, a single-chip silicon pressuresensor (not shown) is used, which includes a sensor cell in which thepressure is introduced to the back side of a diaphragm, and a referencevacuum is provided on the front side of the diaphragm for measuring theabsolute pressure. The pressure sensor is accommodated in a hermeticallysealed to housing 82, which in turn is disposed in the housing 80 of theoverall apparatus for detecting the pressure and the temperature. Alsodisposed in the housing 80 is a conductor plate 83 with capacitors,which are required with a view to electromagnetic compatibility. Theconductor plate 83 also serves the purpose of a connection with flatplug contacts 84, which are disposed in a stub 85 formed onto thehousing 80.

In a pressure stub 88, there is also a temperature sensor 86injection-molded into a tubular plastic sleeve 87, the temperaturesensor being in the form of an NTC resistor, whose terminal lines areelectrically conductively connected to flat plug contacts 84 via inlayparts 90 welded to the NTC wires.

This kind of apparatus for detecting the pressure and temperature is notonly very complicated to produce; for instance, the electricalconnections between the terminal lines of the temperature sensor 86 andof the pressure sensor 82 and the conductor plate 85 and the flat plugcontacts 84 must be made in the fully assembled state by means of asoldered connection. This soldered connection must then be potted forsealing purposes with an adhesive composition 89, for instance.

It is also problematic in such an apparatus that the temperature sensor86 is disposed in a plastic sleeve 87, because this results in what formany applications is an excessively long response time of thetemperature sensor 86.

German Patent Application 197 11 939.5, which was not published prior tothe priority date of the present application, discloses an apparatus fordetecting the pressure and the temperature in the intake tube of aninternal combustion engine in which, to introduce a medium that is underpressure, a stub part secured to the housing and an adapter piececonnected both to the carrier and to the stub part via sealing adhesivesthat decouple mechanical strains are provided.

Such an apparatus does enable very good decoupling of strain by means ofthe adapter, which is connected both to the stub part and to the carriersolely via elastic sealing adhesives. However, its relativelycomplicated manufacture is problematic in such an apparatus. That is,first the adapter has to be secured to the carrier before the stub partcan finally be secured.

Furthermore, strain in the pressure sensor cannot be precludedcompletely, because the carrier is secured to a housing wall and to thatextent is acted upon on one side by pressure that acts on the pressuresensor, so that slight strains can still occur.

It is therefore an object of the invention to refine an apparatus fordetecting the pressure and temperature in the intake tube of an internalcombustion engine as generically defined above in such a way that whilebeing very simple to produce it enables very precise pressuremeasurement.

ADVANTAGES OF THE INVENTION

This object is attained, in an apparatus for detecting the pressure andtemperature in the intake tube of an internal combustion engine of thetype described at the outset, according to the invention in that thehousing includes at least two chambers separate from one another. Onechamber forms a pressure chamber communicating with the intake tube viaa stub and sealed off from the environment. The pressure chamberprotrudes into the part of the carrier on which the pressure sensor issecured, and the other chamber serves to receive and secure theremaining portion of the carrier with electrical connection elements,and for securing the carrier and sealing off the pressure chamber,sealing adhesive connections that decouple mechanical strains areprovided.

Dividing the housing into at least two chambers separate from oneanother, into one of which the part of the carrier to which the pressuresensor with the evaluation circuit is secured protrudes and the otherserves to secure the remainder of the carrier with the electricalconnection elements, where sealing adhesive connections that decouplemechanical strains are provided for securing the carrier and sealing offthe pressure chamber, has the particularly great advantage that the partto which the pressure sensor is secured is acted upon by pressure on allsides in the pressure chamber. As a result, mechanical strains on thecarrier are better avoided than when the sensor is secured to a housingwall, for instance. It is also especially advantageous that intermediateparts of any kind can be dispensed with between the stub and thecarrier, because the pressure chamber communicates with the intake tubedirectly via the stub.

Particularly with a view to simple assembly, to be described in furtherdetail hereinafter, it has proved to be especially advantageous that thehousing includes a base part, on which the stub is disposed and thecarrier plate is secured by sealing adhesive connections that decouplemechanical strains, and a cap part connected to the base part that isdisposed lying above the carrier and has a wall for forming the twochambers, in which the wall is connected to the carrier by a sealingadhesive connection that decouples mechanical strains.

To avoid strains on the cap part secured to the base part that can betransmitted to the carrier and thus to the pressure sensor, it isadvantageously provided that the cap part is secured to the base partsolely via sealing adhesive connections that decouple mechanicalstrains.

Purely in principle, the carrier part to which the pressure sensor issecured can protrude, floating freely, into the pressure chamber. Anembodiment that is especially advantageous for the sake of assemblyprovides that a bearing face is provided on the base part in thepressure chamber, and the carrier is secured to this bearing face by asealing adhesive that decouple mechanical strains.

To protect the pressure sensor from environmental influences, it isadvantageously provided that a ring is disposed around the pressuresensor, and that the interstice between the ring and the pressure sensoris filled with a chemical-resistant gel.

For this purpose, fluorosilicone gel has proved especially advantageous.

To enable an especially direct coupling of the temperature sensor to themedium to be measured, it is advantageously provided that thetemperature sensor is secured to the base part in such a way that itprotrudes into the interior of the stub.

Purely in principle, the temperature sensor can be secured in the stubin various ways.

In one embodiment, it is provided that the terminal lines of thetemperature sensor are clamped to two cheeks formed on the stub by aresilient clip bracket formed onto the stub. In this way, thetemperature sensor can not only be mounted and positioned on the stub ina very simple way, but furthermore, because of the clamping connectionimparted by the clip bracket, it becomes possible to secure the terminallines of the temperature sensor without damage.

To assure that the temperature sensor and its terminal lines will notcorrode or be damaged and attacked by other environmental influences, itis advantageously provided that the temperature sensor and its terminallines are coated with a protective paint or a protective coating,preferably a polyester imide paint.

Particularly with a view to advantageous and simply achieved sealing ofthe terminal lines of the temperature sensor that are extended out ofthe pressure chamber, it is provided that the terminal line of thetemperature sensor is passed through the sealing adhesive connection orsealing adhesive connections between the carrier and the base part.

Another embodiment provides that the temperature sensor is thrust into areceptacle formed in the stub and is secured by an adhesive connectionthat is disposed between the carrier and the base part and surrounds theends of the terminal line of the temperature sensor.

This mode of securing has the advantage in particular that thetemperature sensor can be secured in the stub from above; that is, forsecuring the temperature sensor, the same mounting direction is providedas for securing the pressure sensor.

To prevent corrosion and damage from environmental influences, in thiscase the terminal lines of the temperature sensor are advantageouslyTeflon-coated, except for their stripped ends for electrical contactingpurposes, and it is provided that both the stripped ends and at leastone portion of the Teflon-coated terminal lines are embedded in theadhesive connection. In this way, an especially stable connection ismade, which at the same time is also insulating, because the adhesivecomposition adheres especially well to the stripped, non-Teflon-coatedconnection ends.

To enable especially simple assembly, it is moreover provided in anadvantageous embodiment that for contacting the terminal lines of thetemperature sensor to plug contact pins disposed in the base part andextended to the outside, insulation displacement connections areprovided.

For contacting the terminal lines of the temperature sensor to plugcontact pins disposed in the housing and extended to the outside,conductive adhesive connections and/or soldered connections and/orwelded connections are preferably provided.

The object of the invention is furthermore attained by a method forproducing an apparatus for detecting the pressure and the temperature inthe intake tube of an internal combustion engine, which is characterizedby the following steps:

securing a temperature sensor in a base part of a housing;

making the electrical contacting of the terminal line to plug contactpins which are provided in the base part;

securing the carrier to the base part by sealing adhesive connectionsthat decouple mechanical strains;

contacting the electrical contact elements of the carrier with contactelements that are provided in the base part; and

securing a cap part to the carrier and the base part by means of sealingadhesive connections.

By means of this method, fast and therefore economical production of avery precisely functioning device for detecting the pressure and thetemperature in the intake tube of an internal combustion engine isespecially advantageously possible.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the invention are the subjectof the description below and are shown in several exemplary embodimentsin the drawing.

Shown in the drawings are:

FIG. 1, a sectional view of a first exemplary embodiment of an apparatusaccording to the invention for detecting the pressure and thetemperature in the intake tube of an internal combustion engine;

FIG. 2, a schematic plan view on a clip bracket used to secure atemperature sensor and disposed on the stub part;

FIG. 3, a sectional view of a second exemplary embodiment of anapparatus of the invention for detecting the pressure and thetemperature in the intake tube of an internal combustion engine; and

FIG. 4, an apparatus, known from the prior art, for detecting thepressure and the temperature in the intake tube of an internalcombustion engine.

DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

A first exemplary embodiment of an apparatus for detecting the pressureand the temperature in the intake tube of an internal combustion engine,shown in FIG. 1, includes a housing, designated in its entirety byreference numeral 10, which includes a base part 12 and a cap part 14.

The housing 10 is divided into two chambers, that is, a pressure chamber16 and a further chamber 18 in which a carrier 20 is secured to the basepart 12 by sealing adhesives 22 that decouple mechanical strains. Thecarrier 20 is secured to a rib 13 of the base part 12 in such a way thatthe carrier 20 merely rests on the rib 13. The rib 13 is disposed at thepoint at which bond wires 23 on the carrier 20 are contacted. The bondwires 23 make the electrical connection between flat plug contacts 30,which are disposed in the base part 12, and the electrical connectinglines on the carrier 20.

A pressure sensor 40 known per se is disposed on the carrier 20; it hasa glass base and disposed on that a silicon chip, on whose surface anevaluation circuit, for instance, is provided, which is constructed, forinstance in the form of a Wheatstone bridge, of piezoresistive resistorelements. The diaphragm required for detecting the pressure is made byetching the back side of the silicon chip. The connection of the siliconchip to the glass base is made under a vacuum, so that subsequentlythere is a vacuum in the cavern that is etched out.

The pressure sensor 40 oriented toward the cap part 14 is surrounded bya ring 42, for instance an IC ring. The interstice 44 between the ring42 and the pressure sensor 40 is filled with a fluorosilicone gel. Bymeans of this fluorosilicone gel, it is assured that the pressure sensor40, including its thin-wire gold bonds, are protected against beingtouched and against contact with media, such as gasoline or condensedexhaust gas, present in an engine.

The pressure sensor 40 is disposed on a part 21 of the carrier 20 thatprotrudes into the pressure chamber 16. The pressure chamber 16communicates with the intake tube (not shown) of the engine via the stub15 that is joined in one piece to the base part 12. The evaluationcircuit is preferably applied to the chip of the pressure sensor 40. Itis also possible for the evaluation circuit to be applied to the side ofthe carrier 20 facing toward the cap 40 and located in the pressurechamber 16. In addition to the evaluation circuit, an EMV protectioncircuit can also be provided, for instance outside the pressure chamber,for instance in the chamber 18.

A bearing face 17 may be provided on the base part in the pressurechamber 16, to which the free end of the part 21 of the carrier 20 issecured via a sealing adhesive connection 25 that decouple mechanicalstrains. This connection serves the purpose primarily of assembly andprevents the carrier 20 during assembly from tipping into the pressurechamber 16.

The cap 14 is connected to the base part 12 by sealing adhesiveconnections 27 that decouple mechanical strains as well.

The cap 14, adjacent to the pressure sensor 40, has a wall 19 which isjoined to the carrier 20 via a sealing adhesive connection 28 thatdecouple mechanical strains. By means of this wall 19, a pressure-proofsubdivision of the housing into the two chambers 16, 18 is attained inan especially simple way. At the same time, the wall 19 serves tostabilize the carrier 20.

A temperature sensor 70 is disposed in the base part 12 in such a waythat the temperature sensor protrudes into the stub 15. The terminalline 71 of the temperature sensor 70 extends through the sealingadhesive connection 21 between the base part 12 and the carrier 20.

In the exemplary embodiment shown in FIGS. 1 and 2, the temperaturesensor, in the form of an NTC resistor, is secured by a resilient clipbracket 95 formed onto the stub 15. The clip bracket 95 is shown in FIG.2 in the unmounted state. To secure the terminal line 71 of thetemperature sensor 70, two clamping elements 96, which have detentprotrusions 97 in their front region toward the terminal lines 71 of thetemperature sensor 70, are pressed in such a way into detent openings98, provided on the clip bracket 95, along directions represented by thearrows A that clamping faces 99, formed onto the cheeks 96, come to reston the terminal lines 71 of the temperature sensor 70 and firmly clampthe terminal lines to protrusions 91 which are formed onto the stub part15. The clip bracket 95 is designed such that an O-ring seal 100(FIG. 1) for sealing the stub 15 can be slipped onto the stub 15 onlywhenever the temperature sensor 70 has already been secured to the stubpart 15 by the clip connection described.

The terminal lines 71, bent at an angle, of the temperature sensor 70,after being extended to the outside through the sealing adhesiveconnections 22, are electrically conductively connected to plug contactpins 30 by means of an insulation displacement connection 73, known perse. To that end, the plug contact pins 30, in their lower region, haveV-shaped openings (not shown) into which the terminal lines 71 of thetemperature sensor 70 are pressed in a manner known per se.

Both the temperature sensor 70 and its terminal lines 71 are coated witha polyester imide protective paint, as a result of which not only isprotection against media that act from outside on the temperature sensor70 and its terminal line 70 is achieved, but an especially favorableresponse time of the temperature sensor is also attained.

Disposing the pressure sensor 40 in the pressure chamber 16 as describedassures in an especially advantageous way that the entire pressuresensor 40 is located in the medium acted upon by a pressure, so thatstrains on the pressure sensor, which can occur if the pressure sensoris acted upon by the medium under pressure on only one side, areavoided.

It should be stressed that the bearing face 17, on which the part 21 ofthe carrier 20 to which the temperature sensor 40 is secured rests via asealing adhesive connection 25 is not absolutely required. On thecontrary, the part 21 of the carrier 20 to which the pressure sensor 40is secured can also protrude, floating freely, into the pressure chamber16.

In a second exemplary embodiment of an apparatus for detecting thepressure and the temperature in the intake tube of an internalcombustion engine, shown in FIG. 3, those elements that are identical tothose in the first exemplary embodiment are provided with the samereference numerals, and so the description of the first exemplaryembodiment is referred to in full for describing these elements.

In contrast to the first exemplary embodiment, however, the temperaturesensor 70 is not secured to the stub 15 by a clip connection but ratheris thrust from above into a receptacle provided for it. The terminallines 71 of the temperature sensor 70 are bent at an angle and aresecured at their ends in the sealing adhesive connection 22 disposedbetween the base part 12 and the carrier 20. The terminal lines 71 ofthe temperature sensor 70 are Teflon-coated, except for their ends thathave been stripped for contacting purposes. The sealing adhesiveconnection 22 surrounds both the stripped ends and at least a portion ofthe Teflon-coated terminal lines 71. In this way, especially goodsecuring is attained, because the adhesive composition adheresespecially well to the stripped metal terminal leads.

Also in contrast to the exemplary embodiment shown in FIG. 1, theterminal lines of the temperature sensor 70 are contacted and connectedto the plug contact pins 30 not by insulation displacement connectionsbut rather by conductive adhesive connections, for instance, or weldedconnections or soldered connections.

Furthermore, instead of the bearing faces 17 disposed at the edge of thebase part 12, dotlike bearing faces 17 a are provided, which aredisposed at any point below the carrier 20, for instance below thepressure sensor 40 as shown in FIG. 3.

The pressure sensor 40 shown in FIGS. 1 and 3 is preferably produced asfollows. First, the temperature sensor 70 is secured to the stub 15 ofthe base part 12 in the manner described above. Next, the electricalterminal lines 71 of the temperature sensor 70 are contacted with theplug contact pins 30. This can be done by means of conductive adhesiveconnections, for instance. In that case, the curing time of suchconductive adhesive connections can especially advantageously becombined during a time of sealing adhesive connections to be describedbelow, by which the carrier is secured to the base part.

Next, the carrier 20 is secured to the base part 12 by the sealingadhesive connection 22, which maximally decouple mechanical strains.Then the electrical contacts are made between the conductor tracks onthe carrier 20 and the plug contact pins 30 by means of bond wires 23.Finally, the cap 14 is secured to the base part 12 by means of sealingadhesive connections 19 between the carrier 20 and the cap 14 andbetween the cap 14 and the base part 12, respectively. In this way,because of the design of the cap 14 and the base part 12, the twochambers 16 and 18 are formed; the part 21 of the carrier 20 to whichthe pressure sensor 40 is secured is disposed in the pressure chamber16.

The foregoing relates to a preferred exemplary embodiment of theinvention, it being understood that other variants and embodimentsthereof are possible within the spirit and scope of the invention, thelatter being defined by the appended claims.

What is claimed is:
 1. An apparatus for detecting a pressure and atemperature in an intake tube of an internal combustion engine,comprising a temperature sensor (70), a pressure sensor (40) and anevaluation circuit, the pressure sensor (40) is secured to a carrier(20) for analyzing a measurement result of the pressure sensor with aslittle strain as possible, the temperature sensor (70) and the pressuresensor (40) are disposed in a common housing (10), the housing (10)includes at least a first pressure chamber (16) and a second chamber(18) separate from one another and the temperature sensor (70) isdisposed in a stub (15) of the housing (10), the first pressure chamber(16) communicates with the intake tube via said stub (15) and the firstpressure chamber (16) is sealed off from the environment, said carrier(20) has a first portion (21) and a second portion, said first portion(21) of the carrier (20) on which the pressure sensor (40) is securedprojects into the pressure chamber (16), and the second chamber (18)serves to receive and secure the second portion of the carrier (20)which includes connection elements (23), the carrier (20) is secured atthe housing (10) by first and second sealing adhesive connections (22,28) that decouple the carrier (20) from the housing (10) withoutmechanical strains and sealing off the first pressure chamber (16), andthe temperature sensor (70) has terminal lines (71) which are secured inthe housing (10) by the first sealing adhesive connections (22).
 2. Theapparatus according to claim 1, in which the housing (10) includes abase part (12), on which the stub (15) is disposed and the carrier (20)is secured by the first sealing adhesive connections (22) that decouplemechanical strains, and a cap part (14) is connected to the base part(12) and is disposed above the carrier (20), that cap part (14) has awall (19) for forming the first pressure chamber (16) and the secondchamber (18), and said wall is connected to the carrier (20) by thesecond sealing adhesive connection (28) that decouples mechanicalstrains.
 3. The apparatus according to claim 2, in which the cap part(14) is secured to the base part (12) solely via third sealing adhesiveconnections (27) that decouple mechanical strains.
 4. The apparatusaccording to claim 2, in which a bearing face (17) is provided on thebase part in the pressure chamber (16), and the carrier is secured tosaid bearing face by a sealing adhesive (25) that decouples mechanicalstrains.
 5. The apparatus according to claim 1, in which a ring (42) isdisposed around the pressure sensor (40), and includes interstice (44)between the ring (42) and the pressure sensor (40) which is filled witha chemical-resistant gel.
 6. The apparatus according to claim 2, inwhich a ring (42) is disposed around the pressure sensor (40), andincludes interstice (44) between the ring (42) and the pressure sensor(40) which is filled with a chemical-resistant gel.
 7. The apparatusaccording to claim 5, in which the chemical-resistant gel is afluorosilicone gel.
 8. The apparatus according to claims 1, in which thetemperature sensor (70) is secured to the base part (12) in such a waythat the temperature sensor (70) protrudes into the interior of the stub(15).
 9. An apparatus for detecting a pressure and a temperature in anintake tube of an internal combustion engine, comprising a temperaturesensor (70), a pressure sensor (40) and an evaluation circuit, thepressure sensor (40) and the evaluation circuit are secured to a carrier(20) for analyzing a measurement result of the pressure sensor with aslittle strain as possible, the temperature sensor (70) and the pressuresensor (40) are disposed in a common housing (10), the housing (10)includes at least a first pressure chamber (16) and a second chamber(18) separate from one another and the temperature sensor (70) isdisposed in a stub (15) of the housing (10), the first pressure chamber(16) communicates with the intake tube via said stub (15) and the firstpressure chamber (16) is sealed off from the environment, said carrier(20) has a first portion (21) and a second portion, said first portion(21) of the carrier (20) on which the pressure sensor (40) is securedprojects into the pressure chamber (16), and the second chamber (18)serves to receive and secure the second portion of the carrier (20)which includes connection elements (23), the carrier (20) is secured atthe housing (10) by first and second sealing adhesive connections (22,28) that decouple the carrier (20) from the housing (10) withoutmechanical strains and sealing off the first pressure chamber (16), thetemperature sensor (70) has terminal lines (71) which are secured in thehousing (10) by the first sealing adhesive connection (22) to a basepart (12) of the housing (10) in such a way that the temperature sensor(70) protrudes into the interior of the stub (15), whereby thetemperature sensor (70) is thrust into a receptacle formed in the stuband is secured by the first adhesive connections (22) that are disposedbetween the carrier and the base part and surrounds the ends of theterminal lines (71) of the temperature sensor (70).
 10. The apparatusaccording to claim 9, in which terminal lines (71) of the temperaturesensor (70) are clamped to two cheeks (96) formed on the stub (15) by aresilient clip bracket (95) formed onto the stub (15).
 11. The apparatusaccording to claim 9, in which the terminal line (71) of the temperaturesensor is passed through one or more sealing adhesive connections (22)between the carrier (20) and the base part (12).
 12. The apparatusaccording to claim 9, in which the terminal lines (71) of thetemperature sensor (70) are Teflon-coated, except for stripped ends forcontacting purposes, and that both the stripped ends and at least oneportion of the Teflon-coated terminal lines (71) are embedded in theadhesive connection (22).
 13. The apparatus according to claim 9, inwhich insulation displacement connections (73) are provided forcontacting the terminal lines (71) of the temperature sensor (70) toplug contact pins (30) disposed in the base part (12) and extended tothe outside.
 14. The apparatus according to claim 9, in which conductiveadhesive connections and/or soldered connections and/or weldedconnections are provided for contacting the terminal lines (71) of thetemperature sensor (70) to plug contact pins (30) disposed in the basepart (12) and extended to the outside.
 15. An apparatus for detecting apressure and a temperature in an intake tube of an internal combustionengine, comprising a temperature sensor (70), a pressure sensor (40) andan evaluation circuit, the pressure sensor (40) and the evaluationcircuit are secured to a carrier (20) for analyzing a measurement resultof the pressure sensor with as little strain as possible, thetemperature sensor (70) and the pressure sensor (40) are disposed in acommon housing (10), the housing (10) includes at least a first pressurechamber (16) and a second chamber (18) separate from one another and thetemperature sensor (70) is disposed in a stub (15) of the housing (10),the first pressure chamber (16) communicates with the intake tube viasaid stub (15) and the first pressure chamber (16) is sealed off fromthe environment, said carrier (20) has a first portion (21) and a secondportion, said first portion (21) of the carrier (20) on which thepressure sensor (40) is secured projects into the pressure chamber (16),and the second chamber (18) serves to receive and secure the secondportion of the carrier (20) which includes connection elements (23), thecarrier (20) is secured at the housing (10) by first and second sealingadhesive connections (22, 28) that decouple the carrier (20) from thehousing (10) without mechanical strains and sealing off the firstpressure chamber (16), the temperature sensor (70) has terminal lines(71) which are secured in the housing (10) by the first sealing adhesiveconnection (22) to a base part (12) of the housing (10) in such a waythat the temperature sensor (70) protrudes into the interior of the stub(15), whereby the terminal lines (71) of the temperature sensor (70) areclamped to two cheeks (96) formed on the stub (15) by a resilient clipbracket (95) formed onto the stub (15) and in which the temperaturesensor (70) and the terminal lines (71) are coated with a protectivepaint or a protective coating of a polyester imide paint.
 16. Theapparatus according to claim 15, in which the terminal line (71) of thetemperature sensor is passed through one or more sealing adhesiveconnections (22) between the carrier (20) and the base part (12).